Sound head for thin films



July 4, 1950 J. A. HARINGX 2,513,721

soUND HEAD FOR THIN FILMS Filed May 2, 1946 Patented July 4, 1950 SOUND HEAD FOR THIN FILMS Johannes Adrianus Haringx, Eindhoven, Netherlands, assignor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application May 2, 194e, serial No. 666,768 In Belgium February 8, 1945 Section 1, Public Law 690, August 8, 1946" Patent expires February 8, 1965 jalong a picture gate, thin bands having a. thickness of, say, a few tens of microns such, for example, as lms for taking or reproducing records and more particularly sound records, made from cellulose regenerated wholly or or in part. Since bands of this kind in practice frequently have undulating surfaces it has hitherto been found diicult to guide the band by the common expedients along the picture gate in such manner that the position of the band at the area of the lm gate which is required for flawless recording or reproducing is realised.

In order to avoid the said difliculty, the invention comprises means whereby the band at the area of the gate is invariably maintained in the same plane over only that portion of the band width which is intended for the record or which `comprises the latter. The other band portions, which are not plane, can in this case readily yield to the undulations which their natural form necessitates. Consequently, these undulations cannot exert any detrimental influence on that portion of the band which is to behave substantially as a plane band.

The desired effect, according to the invention, may be obtained, for example, by drawing the portion of the same band width between two plane frames one of which resiliently presses toward the other which is held fixed, and in one of which frames is the sound. According to another form of construction the gate is provided in a guide member which is curved in the longitudinal direction and which is shaped in such manner that the band is stretched along this member in its longitudinal direction solely over the desired portion of the band width. This may be achieved, for example, by giving the member a limited width, but also by means of a local thickened part of the broader guide member, which is provided in the direction of length of the band.

It is evident that it is immaterial for the construction of the device according to the invention which portion of the band width, as viewed in the direction of width, is pressed flat or stretched. If the band only serves as a carrier of, or is intended for taking a sound record or other record, it will generally be stretched tautly over only a central strip. In the case of a soundplus-picture film the taut portion will lie at the margin since the sound record is provided at this area.

Although the device according to the invention is intended in the first place for moving bands which are not plane, it is evident that it can 2 Claims. (Cl. 179-100.31)

2 also serve without objection which are plane,

The invention will be explained more fullyby reference to the accompanying drawing showing, by way of examples, two embodiments thereof, wherein:

Fig. 1 is a cross-sectional view of the embodiment of the invention in Fig. 2 and taken on line I--I thereof,

Figure 2` is an elevational View of the said embodiment of the invention;

Figure 3 is a transverse cross-sectional view of another embodiment of the invention shown in Figure 4 and taken on the line III-UI thereof;

Figure 4 is a side elevational View of the said other embodiment of the invention; and

Figure 5 is a perspective view of the curvilinear member shown in Figure 4.

In Figures 1 and 2, reference numeral I denotes a sound-plus-picture nlm of cellulose regenerated wholly or in part, with undulations, and having a thickness of about 40 microns. The nlm is moved in the direction of the arrow shown via guide rollers 2 and 3. Between the two rollers the margin of the film on which the sound track is provided is led between two frames 4 and 5 which resiliently press on each other and in one of which is the sound gate. By maintaining one of the frames fixed the film is kept constantly in a fixed plane at the area of the gate.

In Figures 3 and 4, the film is designated by 6. As shown in Figure 4, the film 6 runs on rollers 2' and 3 similar to the rollers 2 and 3 shown in Figure 2. However, the sound gate 1, comparable to the sound gate located in one of the members 4, 5 as set forth in the description of Figure 1, 2 embodiment above, is provided in a curved sound member 8 which, according to the invention, comprises in its direction of length a thickened portion 9 by which the margin of the lm is maintained stretched in such manner that at this marginal area the lm is maintained in the same plane over the area of the gate. It can be clearly seen from the figures that the other parts on which, for example, images may be provided or are provided can move freely to accommodate itself, depending on the undulations thereof, while the portion being reproduced remains in the desired plane.

In order to admit of a convenient insertion of the lm the transition area l0 from the guide member to the thickened portion present on it is preferably rounded or beveled.

What I claim is:

1. A device for recording or reproducing oscillations on a thin lrn band a portion of the formoving bands 3 Width of which is adapted to bear the recorded oscillations, comprising a longitudinally convexly curvilinear member having a substantially large radius ofcu-rvature, saidfm'eniber having a face portion extending outwardly therefrom at the convex surface thereof along the major portion of the length of said member, said face portion substantially following the eontourofsaid convex member to likewise be convex, said face portion having a width substantially equal fto'- that of said portion of thelbanda light 'gate'in said face portion, said member being "free 'of flanges in the region of the edges'of-,theband and means for urging said portion of`-the band' in a path where said portion of said-band moves substantially in the plane of and bears'against said convex face portion in the region of said light gate therein and the remaining portion-lof the band in said region rides free, said means being so disposed atseither end of '-said'member that said path deviates 'only lsl-iglfrtly from a straightdine. v

`-2. 4A device-*for recordingorA reproducing oscillations ona-thinlm band as'claimedlin claim 1,

wherein the transition portion between said member and said face portion extending outwardly therefrom comprises a rounded surface,

iwherebyfinsertion of itl-'ie :band onfthedevice is facilitated.

JOHANNES vADRIAIN'U' S HARINGX.

.REFERENCES CITED The.followingreferences are of record in the 

